APS Operational Statistics - Main Page

Welcome to the home page for Argonne National Laboratory's Advanced Photon Source (APS) Operational Statistics. The APS is a third-generation synchrotron x-ray source that provides super-intense x-rays for basic and applied research in materials science, biology and medicine, chemistry, physics, geology, and environmental science. The APS was built by the U.S. Department of Energy as a national user facility.

This page provides access to operational statistics for the APS. Statistics have been kept beginning in the fourth quarter of FY 1996. These statistics are included in FY 1997 data.

Most Recent Downtime Info

Yearly Operation Statistics

Run History Statistics

These displays show the data from all runs beginning in FY 1998.

Definitions of statistics can be referenced by the following:

    Hours Scheduled for User Operation

    This is the number of hours scheduled for the user beam studies. Any other activities during this time must be parasitic. Scheduled time for shielding verification or accelerator studies is not included. All statistics reported are recorded only during the User Operation. Typically, there are 5000 hours per FY scheduled for user operation.

    SR/Xray Availability

    The number of hours that the beam is available to the users divided by the number of hours of scheduled beam delivery prior to the beginning of a run. The specific definition of available beam is that the Main Control Room has granted permission to the users to open their shutters, AND there is more than 50 mA stored beam in the storage ring.

    The APS considers 97% to be the minimum acceptable level for availibility.


    A fault is defined as complete unavailability of beam either via beam loss or removal of shutter permit not related to weather. A fault also occurs when beam has decayed to the point where beam stability and orbit can no longer be considered reliable. At the APS, this threshold is 50mA.

    If a fault occurs within one hour of delivered beam, the APS does not count this as a new fault, but renders the time before the fault and the fault as part of the previous downtime.

    Mean Time Between Faults (MTBF)

    A measure of the average time between faults. MTBF is calculated by taking the delivered beam and dividing by the total number of faults. The APS targets, and routinely exceeds, 70 hours MTBF.
  • Adjusted downtime budgets
Comments and Disclaimer

flood@aps.anl.gov (Randy Flood)